/* DF-2407 full production path: write(fd, buf, 0) on a tpm_ops cdev */
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
int main(int argc, char **argv) {
    int fd = open(argv[1], O_WRONLY);
    char b[16];
    memset(b, 0xAA, sizeof(b));
    if (fd < 0) { perror("open"); return 1; }
    errno = 0;
    ssize_t r = write(fd, b, 0);   /* len == 0 -> tpmwrite -> sc_write(buf,0) */
    printf("write(fd, buf, 0) = %zd errno=%d (%s)\n", r, errno, strerror(errno));
    return 0;
}